15A outlets/switches on 20A circuit

I have outlets on a number of 20A circuits (12/2 wire)- dining area, kitchen counter, den, garage- that appear to be rated 15A. Is this okay? Do wall switches need to be rated according to the circuit amps?

IOW, if the switch can turn the entire circuit off, it needs to be 20A, otherwise, as long as it is sized for the max load it can have, it is fine. Typically, that switch would turn a lamp on/off, and only if that load was the full value of the circuit or was dedicated to that single load, would it need to be a 20A switch.